Estimation of the Final Size of the COVID-19 Epidemic in Pakistan

Faiza Syed; Syed Sibgatullah

The first case of COVID-19 emerged in Pakistan on 26 th February 2020 in Karachi, the most populous city of Pakistan. The patient zero had a travel history to Iran and immediately quarantined upon testing positive for the virus. However, the patient was followed by hundreds of pilgrims returning from Iran which were likely carrying the virus that ultimately led to the spread of COVID-19 into the community. Since then the infections have been increasing exponentially and without proper intervention the situation may escalate enough to overwhelm the already struggling healthcare system in the country. recovered cases (R) are compartments and each individual of a given population will pass through the susceptible phase then to the infected phase and finally to the recovered phase. The SIR model is a steady state model, therefore the population that is analysed is static i.e. no one is being born or is dying. Additionally, the model assumes that once a person is infected, they are immune to the disease and therefore cannot contract it again. The SIR model is ideal for modelling the spread of diseases spread through person to person contact.